This invention relates generally to appliances for correcting malocclusion problems by non-extraction molar distalization methods and in particular to an appliance which uses a forward anchorage assembly, a rearward spring assembly and a threadedly adjustable device extending between the forward and rearward assemblies for achieving distalization.
One of the most well-known appliances used in modern orthodontics for correcting class II malocclusions is the Pendulum Appliance described by James J. Hilgers in the November 1992 issue of the Journal of Clinical Orthodontics in an article entitled The Pendulum Appliance for Class II Non-Compliance Therapy pp. 706-714, which is incorporated herein by reference. The Pendulum Appliance uses a large Nance acrylic button in the palatal area which is anchored by a wire attachment assembly to the upper premolars, in combination with a spring assembly which is attached between the mid-point of the button and the first upper molars to deliver a light continuous force to these molars without affecting the disposition of the Nance button. The spring assembly is connected at its outer ends to lingual sheaths attached to associated banded molars. Adjustment of the spring pressure is by manipulation of the spring assembly. Hilgers"" appliance is an important improvement to the dental art but has limited adjustment capability.
An improved Pendulum Appliance is described in Vol. 67, No. 4 1997 of The Angle Orthodontist entitled Distal Molar Movement Using The Pendulum Appliance pp. 216-270, by Freidrich K. Byloff, et al. which is incorporated herein by reference. This pendulum appliance incorporates molar uprighting bends.
Another appliance is described in U.S. Pat. No. 5,785,520 which is incorporated herein by reference. This patent discloses an appliance using a Nance button having a framework which is anchored to opposed premolars. A pair of spring loaded adjustable pusher elements are interposed between the Nance button framework and lingual sheaths attached to banded molars rearwardly disposed of the Nance button. The telescopic pusher elements are arranged on the lingual side of the dental arch and may be lengthwise adjusted at each side of the arch to vary the force on a banded tooth. The appliance of U.S. Pat. No. 5,785,520 is considerably more complicated in its structural arrangement of parts than the Hilger""s appliance and requires adjustment on both sides of the appliance.
None of the known prior art appliances incorporates a centrally located threaded adjustment feature for applying a variable force on the molars to which distalizing forces are applied.
This orthodontic distalizing appliance uses a threadedly adjustable expansion device for applying distalizing pressure to molars on the lingual side of the dental arch.
The appliance provides advantages which are desirable in a successful distalizing device namely the utilization of an anchoring base such as a Nance button or palatal implant to provide superior anchorage of the appliance; predictable results with a minimum of undesirable side effects; easy accessibility to the adjustment device and ready replacement of the force-applying spring assembly and an overall reduction in patient chair time.
This invention provides an orthodontic distalizing appliance comprising a forward support assembly including an anchoring base adapted to seat in the upper part of the mouth. A rearward spring assembly is provided including spring means having a first portion and at least one outwardly extending second portion, said second portion being removably attached to a tooth. An adjustment means is provided including a forward portion fixedly attached to the base and a rearward portion receiving the spring means in removable relation together with means connecting the first and second portions together in movable relation for applying a force to the second portion of the spring means and the tooth to which it is attached.
It is an aspect of the invention to provide that the adjustment means includes a screw having a first portion attached in freely rotatable relation to the forward portion, said screw having a second portion threadedly connected to the rearward portion so that the rearward portion is movable relative to the forward portion when the screw is rotated.
It is another aspect of the invention to provide that the adjustment means includes a pair of slide rods connecting said first and second portions together in sliding relation.
It is still another aspect of the invention to provide that the screw first portion includes a tool-acceptable portion by which the screw is rotatable to move the forward and rearward portions relative to each other.
It is yet another aspect of the invention to provide that the head of the screw is faceted and adapted to accept a tool in angular relation.
It is an aspect of the invention to provide that the forward portion of the adjustment means includes laterally disposed forwardly extending portions fixedly attached to the base.
It is another aspect of the invention to provide that the anchoring base is a Nance button formed from plastic material and the laterally disposed portions are embedded in said Nance button.
It is still another aspect of the invention to provide that the base includes outwardly extending portions embedded in the Nance button at an inner end and are adapted to be cemented to a tooth at an outer end.
It is yet another aspect of the invention to provide that the spring assembly includes opposed, tooth-attachable sleeves, and outer ends receivable into associated sleeves in removable relation.
It is an aspect of this invention to provide that the adjustment means rearward portion includes a slot, and the spring assembly includes a forwardly extending intermediate portion removably received by said slot.
It is another aspect of the invention to provide that the spring means includes a forwardly extending intermediate portion and outwardly extending portions each adapted to be removably attached to a tooth; and the adjustment means is centrally located and the rearward portion includes a slot receiving the intermediate portion of the spring means in removable relation.
It is an aspect of this invention to provide that the anchoring base is a palatal endosseous implant attached to the roof of the mouth.
It is yet another aspect of the invention that the an adjustment device is attached to the implant by a support means extending between the implant and the adjustment device and another aspect that the support means includes a generally U-shaped wire having a bight portion attached to the implant and rearwardly extending arms attached to the adjustment device.
It is an aspect of the device that the parts may be supplied in kit form to the orthodontic practitioner.
This orthodontic distalizing appliance is relatively inexpensive to manufacture, easy to use and efficient in performing its intended purpose.